1. Field of the Invention
The present invention generally relates to a motor of a ceiling fan and, more particularly, to a motor receiving a plurality of bearings by a sleeve.
2. Description of the Related Art
Referring to FIG. 1, a conventional motor of a ceiling fan with a reference number of “9,” of a Taiwan publication number of I326959 and entitled as “DC Brushless Motor for Ceiling Fan with Improved Stator and Rotor”, is shown, which includes a stator 91 and a rotor 92. The stator 91 has a core 911, a plurality of coils 912 wound on the core 911, and a shaft 913 passing through the core 911. The rotor 92 has an upper shield 921, a lower shield 922 and a waist ring 923 sandwiched by the upper and lower shields 921, 922. Each of the upper and lower shields 921, 922 combines with a bearing 924 for the shaft 913 to couple with, and the stator 91 is received in a room defined by the upper shield 921, lower shield 922 and waist ring 923.
In the above structure, the rotor 92 of the motor 9 rotatably couples with the shaft 913 of the stator 91 via the bearings 924, and, thus, the shaft 913 has to couple with the bearings 924 by press fit, to ensure a stable rotation of the rotor 92 about the stator 91 and to avoid the inner rings of the bearings 924 rotating relative to the shaft 913. In other words, due to the press fit between the shaft 913 and the bearings 924, which can only be achieved by a machine able to apply opposite pressures to the bearings 924 and the shaft 913 respectively, the steps for assembly of this conventional motor 9 are complicated and time-consumptive. Besides, since the conventional motor 9 has a size large enough to operate blades of the ceiling fan, the costs of settling and maintaining said machine are usually high, and, thus, the manufacture cost of the conventional motor 9 is also high.
Additionally, due to the press fit between the shaft 913 and the bearings 924, the vibration caused by operation of the rotor 92 can be easily and directly transmitted to the shaft 913 through the bearings 924, and thus affects electrical devices in the stator 91 or other members connecting with the shaft 913. This transmitted vibration can largely increase the failure rates of said devices and members, and decrease the lifetime of the motor 9 therefore.
As a result, since the conventional motor 9 for the ceiling fan has drawbacks such as a “complicated assembly process” and a “shortened lifetime,” it is necessary to improve the conventional motor 9.
It is therefore the objective of this invention to provide a motor of a ceiling fan with first and second bearings axially clamped and thus coupling with a shaft other than by press fitting, so that this motor of the ceiling fan can be easily assembled.
Another objective of this invention is to provide a motor of a ceiling fan with a resilient member between the second bearing and a second shoulder or between the first bearing and a first shoulder for depressing the vibration generated by rotation of a rotor and reducing the negative affects toward the operation of a stator or members connecting with the shaft due to said vibration, to prolong the lifetime of the motor of the ceiling fan.
One embodiment of the invention discloses a motor of a ceiling fan, which includes a shaft, a bearing sleeve, a limiting member, a stator and a rotor. The shaft has a first shoulder and a second shoulder. The bearing sleeve receives a first bearing and a second bearing for supporting the shaft and has an inner flange, with the inner flange and the first shoulder jointly clamping and positioning the first bearing. The limiting member and the second shoulder jointly clamp and position the second bearing. The stator is arranged around the shaft. The rotor couples with the bearing sleeve.